P161 - Revision and Repeat Revision Rates and the Potential Cost-Utility of Knee Preservation in Young Total Knee Arthroplasty Patients
While it has been proposed that modern implants will outlast previous total knee arthroplasties (TKAs), there is growing concern young patients may experience early failure, revision, and increased medical costs. The purpose of this study was to describe the natural history of primary TKAs by patient age and explore the potential cost-utility of knee preservation interventions and surgery.
Methods and Materials
An institutional total joint registry was retrospectively reviewed for primary TKAs performed 1985-2015 for primary degenerative joint disease. 23,173 records (96.2%) met inclusion criteria with ≥2 years follow-up. Patients were followed for a mean of 8.9 years (range: 2.0–32.2) with 40.6% deceased at final follow-up. Line-itemized revision costs were obtained and categorized by indication to calculate costs due to TKA failure.
Reoperation occurred in 2,417 patients and differed significantly by patient age. 5-, 10- and 20-year survival free of reoperation for patients aged <39 was 86.5%, 77.8%, and 38.4% compared to 94.6%, 92.4%, and 88.3% for patients aged 70–79 (p<0.01). First- and second-time revision rates were significantly higher in younger patients (p<0.01). 1,357 patients underwent one revision, 63 underwent a second revision, and one underwent a third revision. Based on line-itemized costs, average direct in-hospital costs incurred in the first 20 years after TKA for any patient aged <39 years was $14,469. Large potential savings and knee preservation cost utility were observed when delaying primary TKA by 5-, 10- or 20 years in patients <39 ($5,454, $9,467, and $14,469 saved, respectively) and patients aged 40–49 ($3,165, $6,258, and $9,969) (p<0.01).
Even when analyzing only direct, in-hospital costs, patients aged <39 undergoing primary TKA generate greater than $14,000 of costs within the first 20-years of postoperative management, not including initial arthroplasty costs. Age-adjusted cost analyses are necessary when evaluating the relative utility of preservation procedures in comparison to TKA for young patients.